1. Field of the Invention
The present invention is directed to a circuit arrangement for distributing to a plurality of single-ports radio-frequency power supplied to a summation port or for combining in a summation port radio-frequency power supplied from single-ports.
2. Description of the Prior Art
Circuit arrangements of the above-specified kind are known as bridge circuits or Wilkinson couplers (for instance according to an article in NTZ 1962, No. 5, pp. 223-230, or German reference 2,733,888). In the field of electronic engineering they are mainly used for connecting radio-frequency transmitters in parallel. It is also known to construct such Wilkinson couplers either wholly or in part of lumped elements such as coils and capacitors, and it is further known simultaneously to design these lumped elements of the Wilkinson coupler, which simulate the line sections, as a filter circuit and to dimension them in such a way that they will simultaneously act as radio-frequency filters in a signal conditioning branch (German reference 3,527,555). All of these known circuit arrangements require additional absorption resistors. Both in the bridge circuits and the Wilkinson couplers the required additional absorption resistors must be connected at a high voltage level between single-ports, and they must be capable of absorbing the differential power which may occur in case of possible errors in magnitude and/or phase of the radio-frequency power which is fed at the same frequency. The connection of the absorption resistor in symmetry with ground potential has several drawbacks; under all operating conditions the terminals of the resistor have a potential to ground, the resistor must be connected direct to the input of the circuit arrangement so that its position is fixed, and the terminal inductances furthermore result in the input resistance of the circuit becoming unbalanced. For the parallel connection of high-capacity radio-frequency transmitters this absorption resistor must be dimensioned correspondingly large which results in a high thermal load on an extremely small area.